PORTLAND, Ore. - A team of amateur sleuths say they are scouring Oregon and Washington state for clues to the fate of a 1971 airline hijacker who jumped from a plane.

Retired businessman and amateur scientist Tom Kaye said his team of amateur investigators have conducted experiments with money in the Columbia River to try to reconstruct the path taken by some of the cash taken by the hijacker, who called himself D.B. Cooper, The Oregonian reported Friday.

"The money is the only path to what happened to him after he left the plane," he said.

Cooper hijacked a 1971 Northwest Airlines flight from Portland to Seattle. He released the plane's passengers in Seattle, demanded $200,000 and ordered the plane to fly to Mexico City. The hijacker jumped out with the money and two parachutes somewhere over southwest Washington.

The path the team is attempting to trace was taken by about $5,800 in Cooper's $20 that Brian Ingram, 37, discovered in 1980 when he was 8-years-old. Ingram volunteered to join Kaye's team.

Kaye said the team is working for the thrill of the investigation.

"We're doing it for the fun of it," he said. "It's an exciting case, and it's historic. If we add to it, we'll be part of it."